Thermal module

ABSTRACT

A thermal module comprises a flat heat spreader, a fin unit arranged above the heat spreader and a plurality of solid poles interconnecting the heat spreader with the fin unit. The heat spreader defines a chamber therein. A working fluid is filled in the chamber. A wick structure is received in the chamber and attached to an inner wall of the heat spreader surrounding the chamber. The fin unit comprises a plurality of fins stacked together.

BACKGROUND

1. Technical Field

The present disclosure relates to thermal modules, and particularly to a thermal module having a high heat dissipation capability.

2. Description of Related Art

With continuing development of electronic technology, heat-generating electronic components such as CPUs (central processing units) are generating more and more heat which requires immediate dissipation. Thermal modules are commonly used to cool the CPUs.

A conventional thermal module includes a solid metal substrate attached to a CPU for absorbing heat therefrom, a fin unit located on the substrate and a heat pipe. The heat pipe forms an evaporator section embedded in the substrate and a condenser section connected with the fin unit to accelerate a heat transfer from the substrate towards the fin unit. As a manufacturing cost of the heat pipe is high which greatly brings up a cost of the thermal module, usually to control the cost of the thermal module at an acceptable level, only a few heat pipes, such as one or two, are used in the thermal module. Accordingly, a contact area of the heat pipe and the fin unit is limited, and thus heat in the heat pipe can not be timely transferred to an area of the fin unit that distant from the heat pipe, which greatly reduces a utilization rate of the fin unit. A heat dissipation efficiency of the thermal module is limited accordingly.

Therefore, there is a need in the art for a thermal module which can overcome the above described shortcomings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an assembled, isometric view of a thermal module in accordance with an exemplary embodiment of this disclosure.

FIG. 2 is an exploded, isometric view of the thermal module of FIG. 1.

FIG. 3 is similar to FIG. 1, but viewed from another aspect.

FIG. 4 is a cross-sectional view of the thermal module of FIG. 1, taken along a line IV-IV thereof.

DETAILED DESCRIPTION

FIGS. 1-4 show a thermal module 10 in accordance with an exemplary embodiment of this disclosure. The thermal module 10 includes a heat spreader 12, a fin unit 14 and a plurality of poles 16. The heat spreader 12 is flat. The fin unit 14 is located above and parallel to the heat spreader 12. Two ends of each pole 16 respectively connect with the heat spreader 12 and the fin unit 14.

Referring to FIGS. 1 and 2, the fin unit 14 includes a plurality of parallel fins 140 stacked together along a vertical direction perpendicular to the heat spreader 12. The fins 140 are made of heat conductive materials, such as copper or aluminum. Each fin 140 defines a plurality of holes 142 therein for extension of the poles 16. An annular flange 144 is formed at an outer periphery of each hole 142 for contacting a corresponding pole 16.

The poles 16 are made of heat conductive material, such as copper or aluminum. Each pole 16 is solid and column shaped, including a fixed end 161 connected with the heat spreader 12 and a free end 162 extending through a corresponding one of the holes 142 of the fin unit 14. The fixed end 161 and the free end 162 are located at two opposite ends of the pole 16.

Referring to FIGS. 3 and 4, the heat spreader 12 has a profile being substantially rectangular. The heat spreader 12 includes a sealed casing 120, a wick structure 121 and a working fluid. The casing 120 is hollow and defines a chamber 125 therein. The casing 120 is made of metal with high heat conductivity coefficient, such as copper or its alloy. The casing 120 includes a top plate 122 and a bottom plate 124 at two opposite sides thereof. The top plate 122 is planar, whilst the bottom plate 124 is non-planar with a protrusion 126 protruding downwardly from the bottom plate 124 for contacting with an electronic component such as a CPU. Thus, the protrusion 126 is lower than the other portion of the bottom plate 124.

In this embodiment, only one protrusion 126 is formed on the bottom plate 124. Alternatively, the protrusion 126 may be two or more for absorbing heat from plural electronic components.

The working fluid is filled in the casing 120. The working fluid has a relatively low boiling point. The wick structure 121 is disposed in the chamber 125 and attached to a whole inner surface of the casing 120. The wick structure 121 may be sintered powder, tiny grooves or screen mesh. In this embodiment, the wick structure 121 is sintered powder. A plurality of pores are defined in the wick structure 121 to generate a capillary force to the working fluid.

Referring to FIGS. 2 and 4, in assembly, the fixed ends 161 of the poles 16 are evenly fixed on the top plate 122 of the heat spreader 12 by soldering, and the free ends 162 of the poles 16 extend interferentially into the holes 142 of the fin unit 14, and fixed in the holes 142 of the fin unit 14. Thermal interface material such as thermal grease can be applied in the holes 142 to reduce air gaps between the free ends 162 of the poles 16 and the flanges 144 of the fins 14, whereby the free ends 162 of the poles 16 and the fins 14 can be well thermally connected together.

In operation, the protrusion 126 of the casing 120 of the heat spreader 12 contacts with an electronic component for absorbing heat therefrom. Then, the heat is transferred to the chamber 125 of the heat spreader 12. The working fluid in the chamber 125 of the heat spreader 12 absorbs the heat and evaporates. The vapor carrying the heat moves upwardly to the top plate 122 of the casing 120 and releases the heat to the top plate 122; then the heat is transferred to the poles 16 via the top plate 122. The poles 16 transfer the heat to the fin unit 14. Finally, the heat is radiated to outside environment by the fin unit 14. After the vapor is cooled and condensed at the top plate 122 of the casing 120 of the heat spreader 12, the condensed working fluid returns to the bottom plate 124 by the capillary force of the wick structure 121.

Since the thermal module 10 includes a large number of poles 16 which increase a contact area with the fin unit 14 to facilitate heat transfer, and the poles 16 are evenly disposed on the top plate 122 of the heat spreader 12 and evenly disposed in the fin unit 14 so that the heat can be evenly and timely transferred to every area of the fin unit 14, so that the fin unit 14 can be heated uniformly, which greatly increases a utilization rate of the fin unit 14. Thus, a heat transfer capability of the thermal module 10 is increased accordingly.

It is to be understood, however, that even though numerous characteristics and advantages of the disclosure have been set forth in the foregoing description, together with details of the structure and function of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A thermal module, comprising: a flat heat spreader defining a chamber therein, a working fluid being filled in the chamber and a wick structure received in the chamber and attached to an inner wall of the heat spreader surrounding the chamber; a fin unit arranged above the heat spreader; and a plurality of solid poles interconnecting the heat spreader with the fin unit.
 2. The thermal module of claim 1, wherein the fin unit comprises a plurality of fins stacked together, each of the fins defines a plurality of holes for extension of the poles.
 3. The thermal module of claim 2, wherein the poles each are column shaped.
 4. The thermal module of claim 3, wherein the poles are made of one of copper and aluminum.
 5. The thermal module of claim 2, wherein the poles are evenly disposed on the heat spreader and in the fin unit.
 6. The thermal module of claim 2, wherein the poles are interferentially fixed into the holes of the fins of the fin unit.
 7. The thermal module of claim 1, wherein the heat spreader includes a top plate and a bottom plate at two opposite sides thereof, and the poles are fixed to the top plate by soldering.
 8. The thermal module of claim 7, wherein at least a protrusion is formed at the bottom plate of the heat spreader by protruding downwardly from the bottom plate of the heat spreader.
 9. A thermal module, comprising: a flat heat spreader defining a chamber therein, a working fluid being filled in the chamber, and a wick structure being received in the chamber and attached to an inner wall of the heat spreader surrounding the chamber; a fin unit arranged above the heat spreader and comprising a plurality of fins; and a plurality of solid poles each forming a fixed end soldered to the heat spreader and a free end interferentially extending into holes defined in the fins of the fin unit.
 10. The thermal module of claim 9, wherein the poles each are column shaped.
 11. The thermal module of claim 10, wherein the poles are made of one of copper and aluminum.
 12. The thermal module of claim 9, wherein the poles are evenly disposed on the heat spreader and in the fin unit.
 13. The thermal module of claim 9, wherein the heat spreader includes a top plate and a bottom plate at two opposite sides thereof, and the poles are soldered to the top plate.
 14. The thermal module of claim 13, wherein at least a protrusion is formed at the bottom plate of the heat spreader by protruding downwardly from the bottom plate of the heat spreader.
 15. The thermal module of claim 10, wherein the fins are located over the heat spreader and parallel to each other.
 16. The thermal module of claim 15, wherein the fins are parallel to the heat spreader. 